Contemporary laundry treating appliances include vertical axis washing machines having a tub, a basket within the tub defining a treating chamber for the laundry. The tub and basket have aligned top openings that provide access to the treating chamber.
Either an impeller or an agitator are commonly used to impart mechanical energy to the laundry in a vertical axis washing machine. The impeller is more typically used in low water wash systems and relies more on intra-laundry mechanical energy (attributable to the relative laundry movement caused by the impeller) instead of the mechanical energy directly imparted to the laundry from contact with the impeller. The impeller is located within the treating chamber and rotatable about a vertical axis including a base plate with an upper surface including vanes extending above the surface contributes to the mechanical energy necessary to effectively clean the clothes. To effectively wash laundry items in a low water wash system with an impeller, it is helpful for the laundry items to circulate out and back from the center of the impeller. The out and back motion is often in an inverse toroidal motion, with an upward movement at the hub and a downward movement at a periphery of the impeller. In a vertical washing machine with a low profile impeller, an effective movement of the clothes may be hard to obtain particularly in a laundry treating appliance with a reduced level of wash liquid, especially as opposed to a vertical axis agitator with a tall profile.